Arylamine from nitroarenes

Phenols may be prepared by diazotization of the corresponding aniline derivative. The problem simplifies itself, therefore, to the preparation of m-bromoaniline. Recognizing that arylamines are ultimately derived from nitroarenes, we derive the retrosynthetic sequence of intermediates ... 

Arylamines. These compounds are obtained from nitroarenes by reduction with (EtOIjPCl in the presence of A7,A(-diisopropylethylainine. 

From nitroarenes hydrogenation in the presence of aldehydes leads to A-monoalkyl arylamines. Hydrogenation of 2-(o-nitroaryl)-2-cycloalkenones gives annulated indoles (e.g., tetrahydrocarbazoles). ... 

Wrobel Z, Kwast A (2(K)7) 2-Nitroso-79-arylanilines producs of acid-promoted transformation of o adducts of arylamines and nitroarenes. Synlett 1525-1528. doi 10.1055/S-2007-982534 Wrobel Z, Kwast A (2010) Simple synthesis of N-aryl-2-nitrosoanilines in the reaction of nitroarenes with aniline anion derivatives. Synthesis 3865-3872. doi 10.1055/S-0030-1258230 Wrobel Z, Stachowska K, Grudzien K, Kwast A (2011) A(-Aryl-2-nitrosoanilines in the two-step sythesis of substituted 1,2-diarylbenzimidazoles from simple nitroarenes. Synlett 1439-1443. doi 10.1055/S-0030-1260764... 

Catalysed oxidation of primary and secondary amines generally has little synthetic value. Primary amines yield either a mixture of nitriles and amides (ca. 30%) or, in the case of arylamines, the azo derivatives (42-99%) [39], Symmetrical and non-symmetrical azoarenes are also produced in good yields ( 60%) from the reaction of acetanilides with nitroarenes under basic solidtliquid conditions, although higher yields are obtained using TDA-1 [40],... 

To exploit the synthetic versatility of aryl diazonium salts, be prepared to reason backward. When you see a fluorine attached to a benzene ring, for example, realize that it probably will have to be introduced by a Schiemann reaction of an arylamine realize that the required arylamine is derived from a nitroarene, and that the nitro group is introduced by nitration. Be aware that an unsubstituted position of a benzene ring need not have always been that way. It might once have borne an amino group that was used to control the orientation of electrophilic aromatic substitution reactions before being removed by reductive deamination. The strategy... 

---